1. Field of the Invention
The present invention relates to a database, method and program storing medium, and particularly to a database system, a mediating method in the database and a program storing medium for implementing the database system realized by distributing a process for mediating between a user and a database called an agent when there exist one or more users and a plurality of databases.
2. Description of the Related Art
With the recent developments in computers and computer networks, environments in which many computers are connected through a high-speed network are being prepared. Many databases operating in one computer are becoming available.
However, these databases provide different contents with different using procedures. Therefore, it is becoming difficult for a user to retrieve a database most suitable to his or her requirement. It is also becoming a heavy burden for a user to master the different procedures for each database.
For example, although today there exist many document databases on the Internet, it is necessary for the user to know where a database is in order to utilize the database. There is a database in which a document is registered comprehensively, and a database which holds only information on a specific field. Therefore, the user has to select a suitable database meeting his or her needs. Further, the procedures of using databases are generally different. Therefore, the user has to carry out each retrieval process individually while referring to an instruction book for each database.
These days CALS (Common Acquisition and Life-cycle Support) and EC (Electronic Commerce) have become popular. In these activities systems for procuring, managing, advertising, and selling and buying products electronically are being extensively developed and put into practice. However, also in this electronic trade, there are the problems of the selection and using procedure of a database.
For example, purchasers request to obtain the latest information on a product from the database of a plurality of producers, select the producer who meets his or her expectations most satisfactorily, and purchase products from the producer. On the other hand, producers request to find out desirable customers who are interested in his or her products, access a database of purchasers for the purpose of support after they deliver his or her own products to purchasers, and obtain information on the operation of his or her delivered products. In this way, there actually exists a strong need for referring to or utilizing databases reciprocally among companies.
However, differences in format and using procedures of databases often exist, among companies as well as within one company, which is a great obstacle in the reciprocal utilization of databases. When it is used in actual business, it is necessary to protect the security of information and to strictly manage the authority to use, which are other problems.
To solve these problems, a method for using a program called an agent in a network and making the agent mediate between a user and a database is proposed. The agent knows the contents and using procedures of many databases, selects a database, eliminates the differences in using procedure, and verifies the authority to use. From the user's point of view the agent looks a virtual integrated database in which many databases are integrated.
In the technological background described above, when a plurality of users and a plurality of databases exist, the present invention is intended to provide a mechanism for mediating between users and databases. The following users and databases are assumed for this facilitation mechanism. In an environment where a plurality of databases are operated on different models of computers, in a so-called different model distributed database environment, this state often occurs.
Since generally a plurality of users exist, a plurality of formats of requests issued by users and replies received by users exist.
Since generally a plurality of databases exist, a plurality of formats of requests issued by databases and replies received by databases exist.
On this assumption this facilitation (mediating) mechanism of the database system aims to realize the following functions, as shown in FIG. 1. In the diagram are shown a user 1, a facilitation mechanism 2 and databases 3 to 6. In this specification a requesting side and a replying side are called a user and a database, respectively, and the present invention is not limited to a user in a narrow sense and a database in a narrow sense. Generally a person who can request and reply properly, information equipment, programs, etc. can be a requesting side (a user in the present invention) and a replying side (a database in the present invention).
The process from receiving a request to databases 3 to 6 from a user to replying to the request, in the facilitation mechanism 2, is shown below. The following items (1) to (5) correspond to processes (1) to (5) shown in FIG. 1.
(1) A facilitation mechanism receives a request according to an output procedure designated by a user
(2) The facilitation mechanism selects a database suitable for processing the request out of databases 3 to 6 according to the request of the user 1. A plurality of databases can be often selected.
(3) The facilitation mechanism sends the request according to an input procedure designated by the selected database.
(4) The facilitation mechanism receives a reply according to an output procedure designated by the selected database. When a plurality of databases are selected, the facilitation mechanism collects a plurality of replies.
(5) The facilitation mechanism sends the reply according to an input procedure designated by the user 1.
To simplify this facilitation mechanism, a method using a concentrated configuration can be considered. FIG. 2 explains a facilitation mechanism based on a concentrated configuration of mediating functions.
The concentrated configuration of a facilitation mechanism means a configuration where a facilitation mechanism 14 implemented by a program receives outputs from all the users 11 to 13, and inputs the outputs to all the databases 15 to 18, as shown in FIG. 2. After replies from the databases 15 to 18 are collected in the facilitation mechanism 14 by the reverse procedure, they are sent to the respective users who asked the questions. However, this concentrated configuration has the following problems.
Concentration of Load at the Time of Operation
Since all mediating work is carried out by one program, the load tends to become heavy. An increase in the number of users and databases directly leads to an increase in load, and the load cannot be distributed.
High Costs of Operation Managing Costs
If the operating form of the database system is that users and databases are registered with the database system, a design modification of a program is required every time the number of users and databases increases, which affects the whole system. Also a modification of the program is required every time an input/output format is modified, deleted or added, which also affects the whole system.
Cannot Protect the Security of Information
For example, although which database can receive which request can be confidential information in some cases, the security of such information cannot be protected, since in the concentrated configuration the information is collected in one place. For example, the facilitation mechanism 14 shown in FIG. 2 can access all the databases 15 to 18, and a manager of the facilitation mechanism 14 can obtain information from the databases 15 to 18 without any restriction.